A nonparametric scale analysis of the development of conservation

Abstract

The purpose of this study was to investigate the development of conservation by using the nonparametric Mokken scale analysis. Subjects were 801 children from kindergarten and primary school Grades 1 and 2 who completed 13 conservation tasks derived from Piaget’s publications. It was shown that some selections (i.e., seven, eight, and nine tasks, respectively, at three successive administrations with three-month’s interval) formed strong Mokken scales, which were invariant for different samples at the same point in time of test administration. Furthermore, it was found that during the course of development the number of tasks which fitted on the scale increased. However, some reversals of the relative positions of a small number of tasks were found for the scales at different points in time of test administration. It was concluded that application of nonparametric Mokken scale analysis resulted in a new, but very useful instrument for analyzing the order of acquisition of conservation.